Asaphopsoides yongshunensis

Order Asaphida / Superfamily Remopleuridioidea / Family Hungaiidae

asaphops, Asaphopsis, a trilobite genus name; -oides, resembling, similar to

Yongshun, Yongshun County, Hunan, type locality of the type specimens

Xiangxiia yongshunensis

A large trilobite with smooth dorsal shield. Cephalon semi-elliptical; cranidium trapezoidal; glabella weakly convex, conical, with two pairs of glabellar furrows; occipital furrow deep laterally and wide-shallow medially; dorsal furrows forming deep pits on both sides of the front of the glabella; palpebral lobes crescentic, medium-sized, in the mid-posterior part of the glabella; anterior border long and wide-flat; posterior wings transversely extremely long with a spherical end; anterior branches of facial sutures long, meeting on the anterior median line; posterior branches extending nearly horizontally, cutting the posterior border; fixigenae narrow; librigenae wide, tapering anteriorly to meet on the cephalic median line, genal spines slender and long. Thorax of 13 segments; axis narrow, tapering from the 8th segment onward; pleurae straight, interpleural furrows deep, pleural spines sharp. Pygidium elliptical; axis narrow and long, tapering posteriorly with rounded end; pleural region wide with distinct backward-curved pleural segments; border wide and flat, with a pair of small marginal spines laterally.

This species is one of the largest Chinese trilobites, commonly known as the "big pancake". Liu Yiren (1982) recorded the largest individual at 33.5 cm long and 18.4 cm wide.